Influence of spoliation in poly(2-hydroxy ethyl methacrylate) soft contact lens on its free volume and optical transparency

Deepa Urs, M. V. and Ranganathaiah, C. (2008) Influence of spoliation in poly(2-hydroxy ethyl methacrylate) soft contact lens on its free volume and optical transparency. Journal of Materials Science: Materials in Medicine, 19 (3). pp. 1355-1361. ISSN 1573-4838

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Abstract

The calcification in poly(2-hydroxy ethyl methacrylate) contact lens was investigated using positron annihilation spectroscopy (PLS). The two poly(2-hydroxy ethyl methacrylate) (PHEMA) lenses of different companies were calcified employing a simple mechanism of calcification in abiotic aqueous solutions. The calcium deposit was analyzed using energy dispersive X-ray spectroscopy (EDS). Calcified lenses showed decrease in ortho-positronium (o-Ps) lifetime and free volume hole size of the lens material suggesting diffusion of Ca2+ into these cavities. The change in optical property viz. refractive index of these calcified lenses were measured and correlated with positron results. To find a better correlation, a series of worn spoilt PHEMA lenses of the same power with mainly calcium deposits, were similarly characterized using PLS and refractive index. These results correlate well with the free volume of the material. For hydrophilic lenses this correlation is reported for the first time.

Item Type:	Article
Subjects:	D Physical Science > Physics
Divisions:	Department of > Physics
Depositing User:	Manjula P Library Assistant
Date Deposited:	23 Aug 2019 11:25
Last Modified:	23 Aug 2019 11:25
URI:	http://eprints.uni-mysore.ac.in/id/eprint/6989

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